Photographic roll-film.



No. 700,684. Patented May 20, I902.

' B. HAUSDOBF.

PHOTUGBAPHIG BULL FILM. (Applictlon filed Feb. 28, 1900. Renewed Mar.19, 1902.)

(No Model.)

THE mums pmm m. nimouma, mailman). d c.

UNITED STATES ATENT FFICE.

ROBERT HAUSDORF, OF BERLIN, GERMANY, ASSIGNOR TO AOTIEN GESELL- SCHAFTFUR ANILIN FABRIKATION, OF BERLIN, GERMANY.

PHOTOGRAPHIC ROLL-FILM.

SPECIFICATION forming part of Letters Patent No. 700,684, dated May 20,1902.

Application filed February 28, 1900. Renewed March 19, 1902. $erial1l'o.9&962- (No specimens.)

To all whom, it may concern.-

Be it known that 1, ROBERT HAUSDORF, of Berlin, in the Kingdom ofPrussia, German Empire, have invented new and useful Improvements in theProduction of Photographic Roll-Films; and I do hereby declare that thefollowing is a full, clear, and exact description of the invention,which will enable others skilled in the art to which it appertains tomake and use the same.

In the practical use of photographic rollfilms designed for insertioninto and removal from cameras in daylight it is the universal custom toprovide a considerable length of black paper, linen, or the like as aWrapper or covering to exclude the light from the sensitized surface ofthe film. This covering is always colored by means of dyestuffs.Moreover, it is bleached, glued, and contains other chemical substances,such as blanc fixe, &c. The contact of all these substances with thesensitized coating may affect the latter most injuriously by renderingit less sensitive or by destroying part of it by reduction. Thecovering, moreover, being in consequence of its composition more or lesshygroscopic, absorbs moisture from the atmosphere and transfers it tothe film, which, therefore, even after a short time, may be destroyed,the films being, as is well known, stable in a perfectlydry state only.There is another inconvenience in the covering having figures and marksprinted on the back in order to indicate what section of the film isbeing exposed. These signs, being easily transferred to the sensitizedsurface by pressure, may likewise pass into the negative and'spoil theprints produced therefrom. Many attempts have been made in order toavoid these drawbacks. Trials have been made to manufacture the wrappersin such a way as to avoid in the same any constituents likely toaffectinjuriously the sensitized film, but without success. It has .furtherbeen proposed to dispense altogether with a covering and to fix theenveloping paper only at each end of the sensitized paper. In thislatter case it was necessary to mark on the film the size of thenegative by means of perforations, and a mechanical apparatus had to beapplied which by catching into the perforated holes indicated when a.section of the film had advanced. It is evident that this arrangement isa most complicated one. Moreover, it did not warrant full security.

The accompanying figure illustrates a piece of film, wrapper, andcoating constructed in accordance with my invention.

Now I have found that all these inconveniences can be avoided in asimple and ready manner by coating the wrapper a, which comes intodirect contact with the sensitized surface of the film b, with a thinlayer 0 impermeable to water. This layer will prevent injuries to thefilm through atmospheric moisture or through such ingredients of thecovering body as might be obnoxious. It will likewise prevent the marksand figures printed on the Wrapper from being transferred to thesensitized surface.

In order to carry out my invention, I coat the enveloping body withcollodion or with such solutions of resins as after evaporation of thesolvent yield a layer impermeable to water.

Having now described my invention and in what manner the same is to becarried out, What I claim as new is Photographic roll-films having acoating, impermeable to water, onthe wrapper or covering which comesinto direct contact with the sensitized film. I

In witness whereof I have hereunto signed my name, thisl2th day ofFebruary, 1900, in the presence of two subscribing witnesses.

ROBERT .IIAUSDORF.

Witnesses:

WOLDEMAR HAUPT, HENRY HASPER.

